package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IFollowService followService;
    @Override
    public Result queryBlogById(Long id) {
        Blog blog = getById(id);
        if(blog == null){
            return Result.fail("不存在");
        }
        //查询blog有关的用户信息
        // 查询用户
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
        //查询用户是否点赞
        isBlogLike(blog);
        return Result.ok(blog);
    }

    /**
     * 查询用户是否点赞
     * @param blog
     */
    private void isBlogLike(Blog blog) {
        //1.判断当前用户是否已近点赞
        UserDTO user = UserHolder.getUser();
        if(user == null){
            //用户未登录 无需查询是否点赞
            return;
        }
        Long userId = user.getId();
        String key = RedisConstants.BLOG_LIKED_KEY+blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            Long userId = blog.getUserId();
            User user = userService.getById(userId);
            blog.setName(user.getNickName());
            blog.setIcon(user.getIcon());
            //查询用户是否点赞
            this.isBlogLike(blog);
        });
        return Result.ok(records);
    }

    /**
     * 点赞博文
     * @param id
     * @return
     */
    @Override
    public Result likeBlog(Long id) {
        //1.判断当前用户是否已近点赞
        Long userId = UserHolder.getUser().getId();
        String key = RedisConstants.BLOG_LIKED_KEY+id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if(score == null){
            //不存在
            //2.如果未点赞 则可以点赞
            //2.1 数据库点赞数加1
            boolean success = update().setSql("liked = liked + 1").eq("id", id).update();
            if(success){
                //2.2 保存用户到redis的Zset集合中 zadd key value score
//                stringRedisTemplate.opsForSet().add(key,userId.toString());
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else{
            //3.如果已点赞 取消点赞
            // 3.1数据库点赞数减1
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            if(isSuccess){
                //3.2 把用户从redis的set集合中移除
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    /**
     * 查询点赞列表
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {
        String key = RedisConstants.BLOG_LIKED_KEY+id;
        //1.查询top5的点赞用户 zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        //2.解析出其中的用户id
        List<Long> userIds = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", userIds);
        //3.根据用户id查询用户 where id  in (5,1) order by field(id,5,1)
        List<UserDTO> userDTOList = userService.query().in("id",userIds)
                .last("order by field(id," + idStr + ")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        //4.返回
        return Result.ok(userDTOList);
    }

    /**
     * 保存博文
     * @param blog
     * @return
     */
    @Override
    public Result saveBlog(Blog blog) {
        //查询当前登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        //2.保存探店笔记
        boolean isSuccess = save(blog);
        if(isSuccess){
            //3.查询笔记作者的所有粉丝 select * from tb_follow where follow_user_id = ？
            List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
            //4.推送笔记id给所有粉丝
            for (Follow follow : follows) {
                Long userId = follow.getUserId();//粉丝id
                String key = RedisConstants.FEED_KEY+userId;
                stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
            }

        }

        //5.返回id
        return Result.ok();
    }

    /**
     * 滚动分页查询关注的笔记
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        //2.查询收件箱 ZREVRANGEBYSCORE key Max Min LIMIT offset count
        String key = RedisConstants.FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        //3非空判断
        if(typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        //4.解析数据：blogId，minTime(时间戳），offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) {
            //4.1获取id
            ids.add(Long.valueOf(tuple.getValue()));
            //4.2 获取时间戳
            long time = tuple.getScore().longValue();
            if(time == minTime){
                os++;
            }else{
                minTime = time;//时间戳
                os = 1;
            }
        }
        //4.根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("order by field(id," + idStr + ")").list();
        blogs.forEach(blog ->{
            Long blogUserId= blog.getUserId();
            User user = userService.getById(blogUserId);
            blog.setName(user.getNickName());
            blog.setIcon(user.getIcon());
            //查询用户是否点赞
            this.isBlogLike(blog);
        } );
        //5.封装并返回
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setOffset(os);
        scrollResult.setMinTime(minTime);
        return Result.ok(scrollResult);
    }
}
